Topology-Reconfigurable Fault-Tolerant LLC Converter With High Reliability and Low Cost for More Electric Aircraft

Thanks to the advantages of high fuel efficiency and low emission, more electric aircraft (MEA) has attracted increasing attention in recent years. For MEA, high reliable power converters which can keep working after multiple unexpected faults, are highly desired in the electrical power system to guarantee safety. In order to fulfill the high reliability requirements, a novel fault-tolerant LLC converter is proposed for MEA in this paper, which can keep working after two ideal shorted-circuit faults occurred on switches with a redundant circuit and topology reconfiguration. The redundant circuit is employed to achieve the first fault-tolerant ability, and when the second switch failure occurs, the proposed converter would be auto-reconstructed with the aid of two additional diodes to ensure uninterrupted operation. Because only two extra diodes are added to achieve the second fault-tolerance, the system reliability is significantly enhanced with low additional cost. Moreover, both the voltage/current stresses and the small-signal models of proposed converter are approximate in all prefault and postfault modes, contributing to simplified circuit design and reliable control system. Finally, a 500 W prototype is designed and built to experimentally verify the advantages of proposed fault-tolerant LLC converter.